<template>
    MyLeft组件
    <div>
        count: {{ count }}
        <button @click="count++">+1</button>
    </div>
</template>

<script setup>
    import { ref, onMounted, onUnmounted } from 'vue';
    const count = ref(0)

    onMounted(() => {
        console.log('MyLeft组件被挂载了')
    })

    onUnmounted(() => {
        console.log('MyLeft组件被销毁了')
    })
</script>